Spring to Snow, Winter Cold, & Rain. Sounds Like March!

It’s days like today that keep us going when the winter blues are knocking on the door. You glance at the 7-Day, utter a few expletives, but then look out the window. Go for a walk outside. And the warm sun and birds chatting erase all those cold thoughts for a little while. Your medium regular switches to a large iced coffee, and you hit the streets without (gasp!) 14 layers on. Hope you all got a chance to soak in the warmest weather since you were preparing your Thanksgiving turkey, because we’re going to need those memories by Thursday morning. At least with Daylight Saving Time many have the chance to enjoy the evening before the dark/cold settle in.

This next storm system will be an absolute beast for northern New England, but shouldn’t feature the same sorts of headlines around here locally. It all starts out with increasing clouds tonight, especially after midnight. That will help cap overnight lows in the 30s. Tomorrow morning a weak area of lift will try to stretch out in our direction, and may be enough to spawn some scattered rain/snow showers north of the Pike. The best shot of this would be in southern New Hampshire or along Route 2 in MA, and doesn’t look like anything major. The GFS is the only model that wants to bring more substantial precip into the area during the morning, so I’m throwing that one out. And even if you see some flakes, the warmth from Tuesday should have helped to heat up the road surfaces a bit and will aid in melting upon impact. Good things.

Most of the morning hours through midday look pretty quiet. Clouds, chilly temperatures from Boston – NW, and milder air for far SE Mass climbing through the 40s and perhaps reaching 50 by the late afternoon. It’s the towns NW of Boston that should stay very chilly, as a NE wind drains the cold down from Maine and keeps everyone stuck in the 30s to near 40.

As the day continues and the storm approaches, a flood of milder air is expected to come in aloft (a few thousand feet up). That should help change any precipitation over to rain, even into southern NH. There’s still a little uncertainty on where exactly that line moves up to, as each model presents a little different take on it. The mix may move all the way up into Concord or perhaps a few miles north of the city before halting. The rain shower activity will pick up in intensity and coverage during the afternoon and evening, so expect a soggy but not icy ride home from work. Where snow is on the ground, which is most everywhere, this will also probably lead to some locally dense fog developing.

Check out the jackpot zone! Most of northern New England gets pasted with snow from this storm. There is some data that suggests 24″ may be conservative for some of the mountains, where up to 3′ may be able to accumulate. Either way, a widespread heavy snow that will ensure that ski season will go as long as people want it to go this year. Adirondacks, Northeast Kingdom, White Mountain Region, and much of Maine are the winners.

Wednesday night is the main ‘go-time’ for us, as the storm crosses Cape Cod, starts to head off to our NE, and sees its central pressure drop all the way down into the 970s (millibars). As it passes it will drag down cold air rapidly, both aloft and at the ground level. It looks like most of this transition will take place after about 9pm, starting in extreme northern MA and then heading south. By the pre-dawn hours on Thursday surface temperatures will be plummeting down into the 20s and even some 10s! So flash freezing will be a concern, and anyone on the roads late Wednesday night into Thursday morning should expect some really treacherous conditions. Also worth noting that it will be difficult to pre-treat any roads, since there will be some pretty hefty rain coming down before the change.

Plus, snow will be falling at this point as the colder air funnels in aloft. It looks like just about everyone, even down to Cape Cod, will see this transition. The main push of moisture is to the north of us so we’re not expecting huge totals and ‘backlash’ snow rarely ends up being big, but it’ll be enough to coat the ground and freeze up with the cold air. By far and away, the Thursday am commute will be most impacted. There may be cause for some school delays, but it’s a bit too early to know that for sure. The snow showers should wind down by late morning, leaving us with the cold.

The latest snow depth in the region, pre-storm. Very conceivable that some of the higher terrain will have 60″ of snow on the ground by midday on Thursday. Let’s hope the melt comes slow this spring, otherwise flooding would be a concern.

One tool we look at, SREF (Short-range ensemble forecast) plumes. All different members of one ‘team’, all tweaked slightly to get different results. When they’re in very good agreement or ‘cluster,’ it’s a good sign for the forecast. This one for Burlington shows the massive snow potential. While it may be overdone, one of the only other times I’ve seen numbers this high was for the February 2013 blizzard in Boston. Time will tell how much actually falls, but it’ll easily top a foot and perhaps top 2′.

Speaking of that cold, Thursday looks downright brutal for this time of year. The actual high temperature for the day will be at midnight, so we won’t be breaking any daytime records. But most of the day will be spent in the 20s, even falling into the 10s for the higher terrain by the evening. That’s effectively more than 20º below average for the date! So the 50s to low 60s we saw on Tuesday will feel like a distant memory.

Unfortunately, it’s not just the cold we’ll be living with, but the wind. With such a strong storm to our NE continuing to ‘bomb out’ and extremely cold air above our heads, mixing will be deep and gusts could reach 50mph on Thursday. Not only could this create some power outages to our north where wet snow falls, but it will create wind chills in the single digits during the daylight hours on Thursday. That’s quite a feat for mid-March.

As a quick ridge of high pressure builds in at night we should see temps go way down into the single digits and perhaps even a few subzero towns. Across central/northern NH/VT/ME where fresh snow is deep, there should be plenty of subzero temps. Boston’s record low for Friday morning is 12, and Worcester is 4. Both should be in range. Another chapter in our epic winter! Fortunately, after the frigid start on Friday, warmer air will rapidly be pushing in ahead of our next weather system. We should manage the 30s to low 40s, which should feel pretty great relatively speaking.

The classic March roller-coaster continues as we head into the weekend. Before a front arrives on Saturday we should see temps rise into the 40s to near 50, then deal with some scattered rain showers. Nowhere near a wash-out, just some drops to dodge. This front brings the next blast of cold, which looks like a handful. Highs will stay in the 30s on Sunday for many of the big St. Patrick’s festivities, and by Monday 1000mb-500mb thicknesses plummet into the 490s again for parts of New England! Ooof. There’s an outside shot we stay in the 20s yet again on Monday (St. Patrick’s Day), and go into the single digits again at night. The cold will stick around for Tuesday.

There are a couple models hinting at possible storminess by late next Monday/Tuesday, but it’s far from certain right now. With so much Arctic air in place my inclination would be to say any storminess will stay suppressed to our south and head out to sea. The 500mb spaghetti plots show the massive uncertainty right now, whereas just about anything could happen during that time frame. So it’s just a ‘wait and see’ for now.